Throttling and unloading valve



Patented Sept. 30, 1947 THROTTLING AND UNLOADING VALVE John Kanuch,Cleveland, Ohio, assignor, by

mesne assignments, to Borg-Warner Corporation, Chicago, Ill., acorporation of Illinois Application December 12, 1942, Serial No.468,858

1 Claim. (Cl. 137-153) This invention relates to an improved valve foruse in vacuum systems and the like.

The invention is directed primarily to an improved form of valvearrangement in a system between an evacuating means such as a vacuumpump, and a device or instrumentl operated lon `the vacuum createdthereby, said valve means being such that the vacuum pump is relieved ofthe vacuum load when the difference in pressure between two independentpoints in the system, such as between a cabin or an airplane andatmospheric pressure reaches a certain predetermined amount.

In the operation of airplane instruments, for example, the instrumentsare normally operated on a vacuum equal to the vacuum pulling about fiveinches of mercury at sea level on. one side of the instrumentsand cabinpressure on the other side. Ordinarily this vacuum should be maintainedfairly constant.

It is an object of th'e present invention to disclose a valvearrangement Vwhich will unload the pump automatically when thedifference between atmospheric pressure and the pressure in theinstrument room or cabin is greater than the vacuum needed to operatesuch an instrument. In this connection, at altitudes wh'ere the cabinsupercharger of an airplane, for example, is operated and thereby raisesthe pressure in th'e cabin, while the pressure of the outside atmosphereis dropping, the device herein. disclosed will respond to the diierencebetween cabin pressure and atmospheric pressure, and will unload thepump more and more after a certain altitude is reached until theatmosphere draws the entire vacuum and the pump has no load.

This unloading action conserves fuel and transfers the additional powerfrom the pump back to the motor.

It is a further object of this invention to provide an improvedconstruction in which the device acts as a. throttling valve when thepressure in the cabin and the outside pressure do rnot diiier enough toopen' the valve and unload the pump, but when the pump is pulling agreater vacuum than is needed.

It is another object of this invention to provide a device in which theconstruction is relatively simple and inexpensive, and has few workingparts to get out of order.

Other objects and uses of this invention will become more apparent fromthe following description when taken with the accompanying drawing, inwhich:

Fig. 1 is a schematic view illustrating the present invention asapplied. to the vacuum systemv of an instrument for. an airplane andthe. like; and

Fig. 2 is a vertical cross-sectional view of the assembly disclosedherein.

Referring more in detail to the constructionshown in the iigures, andreferring first to Fig. 1, there is illustrated an airplanel, shown inoutline form by means of dotted lines, having a cabin I2 of Va typewhich may be supercharged.

There is also provided the instrument panelr I4 within the cabin, theassembly I6 forming the subject of the present invention, the vacuumline i8 from the instrument panel to the valve, the vacuum pump 20, apump line r22 from the valve assembly I6 to the pump, what may betermeda cabin line 24 leading fromv the cabin and carrying cabinlpressure to the Valve assembly |6 and a filter 26, having what may betermed a lil-y ter line 28, leading from the lter to the valve assembly.

This illustrates schematically the invention herein as it might normallybe arranged in .such a vacuum system.

Referring to the construction shown in Fig.'-

2, there is illustrated a valve assembly such as" disclosed herein. Thiscomprises a. housing 30, which is shown as generally cylindrical inshape, provided with' a base 34 and cover 35.

The housing 30 has the vacuum chamber 32, with a connection to theinstrument line I8 andanother connection, the connecting line 22,leading to the inlet side of the pump 29. The housingV 3l] is provided,as above mentioned, with the base 34 which' comprises the end closure ofthe cylinder. It has, ordinarily, an airtight t with the bottom of thehousing 3B, and may be attached thereto by machine bolts, or the like,36.

The base 34 has an upstanding valve stem receiving member 38 receivingand retaining the stem 39 of the valve 40 in vertical alignment whilevallowing th'e valve 40 to move longitudinally as'V isclearly apparentfrom the drawing.

This valve stem receiving and retaining member 38 is provided with abearing surface for the valve stem 39. stem receiving member 38 ispreferably provided with a small hole or opening 4| below the normal'position of the bottom of the valve-stem for thepurpose of breaking anyair pressurebeneath the valve stem 39, so that said stem iscapable ofmoving longitudinally within the valve receiving; opening of the member38. The housingA 30'ls.: likewise provided with what may be termed asec-' bushing 42 forming 'a'- The valvev ond or atmospheric chamber 46,and with a third or head chamber 48.

The atmospheric chamber 48 has means comprising the filter line 28,communicating With the filter 28 and maintaining atmospheric pressureinside of said chamber 46.

The head chamber 48 preferably has an opening communicatinglwiththeatmospheric chamber 46, said opening-being numbered' 50; anda secondopening or port 24 communicating with and forming part of the cabin line24 leading to:` the cabin l2.

The housing 30 is normallyprovided- Withthecover 35, which seats on apressure responsivevk means comprising a diaphragml54; andthe cover- 35and diaphragm 54 are attached.to-*the*housingTV provid-edwvithanannulanseating Vledge at 8l andi.

said'valvestem 39`f is attached to the diaphragm 54 by meanso-Wasl'iersor the-like (i2 and 64,' the latter. offwhicl' seatsfontlie annularledgel 6! of the? valvestem-i 39fand 4is retained tightly; in placebyrthe-lnut.

Asabbve mentioned? there is provided the valve dislesf44i'AThis'ivalvediscuis preferably integral veitlrthefvalve/'stemL39.V Thedisc 44 seatson the valve seat lfwithwhich-it forms a substantiallyar-tiglit'seal preventing gas under pressure from passing ibetween'the-fvacuumf chamber 32'and the atmospheric'chamberiiayhenthe valvel isseated.

The valve disc 44 is urged against the valve seat eatifalltimeslby,aatensionxmeans .such as by the spring-110:.' Preierablysj thiscoilspring 'lili is of a size and type to exert a pressure-against 'thedisc sustaining-thee discY infnormal"loperationV againstae-predeterminedfvacuum ofsthey amount desired.

Thaya-Ive assembly disclosed herein may beiputftogethereiniany:convenientfmanner; Oneway is to insert the Vsterre`3914;:f1the=valve14ilin the.. centen, opening on ,thespider-lfwhile theibase plate Shand thecover35iare'removed. Therwasher 64' issthensseatedonithefledgef'l and-the diaphragm gtisplacedon thefva-lvastem` 38foverthe WasherA 64o The-secondiwashery seatsfonzthe Valve stem 3,9eover thediaphragmand the washers are tightly clamped` againstthefdiaphragm andon the valve stem 3,9'- 'bylthreadingq on" the .nut E6.' The valve 48 isthenc-movedto-.a position where the diaphragm 54-may beclampedrin, placeby placing the covert 35. thereon and: tighteningV the machine`l'el'ts-l 53 toclamp the; cover; against the diaphragm. The position ofthe Valve when the cover is clamped onithe diaphragm should be suchthat. after:- theacover -is-` in.- place thevalve may be movedcto thepositionf shownv in iig; 2 and the diaphragm 54e Will-athenllbe-tautlThebase 34, withu the spring 'lil inf place around the valvestem.rec`eiving,fmember 38; may be moved into position so thattheva-lve` stem 39 will enter the opening .provided therefor:` in the-valve' stem `reoeivingimember 38,u andthe springfl will pressagainstlthembottom of-thevalvedisc 44, moving-riigtostheseatingfpositioniagainst the valve seat housing 38 by means ofthe machine bolts 36. The assembly is then ready for attaching to thefilter line, the instrument line, the pump line, and the cabin line,above described.

It is understood that the assembly may be put together in any orderdesired, but the above is one Way in which it can be done and serves toillustrate such assembly.A

In' operation, for example wheni the airplane is on the ground, and thecabin is not superi charged, the pump 22 will create a vacuum of thedesired amount in the chamber 32 and the pump line and instrument line.

When the vacuum in the chamber 32 is greater 15;, than they desiredvacuum, it will exert a pull on vthe disc 44-'suicient to overcome atleast some of the tension of the spring 18 and Will move the disc out-ofvthe seating position on the valve seat 88..` This4 condition may occurwhen the motor is raced and the pump isf-running at higher than normal.operating speed. 'I'.hevalve disc 44 under such circumstances fwillfunseatj onlyenough to admit, Yintovacuum'chamberii?t'miuantity oairjust sufcientito balancejthe 'excess vacuumover,

that desired, and it'will seat'. againwhenthe vacuum'is balancedV Asthe'plane rises,V the` atmospheric pressure ing thechamber 45decreases.Tliislexerts` no par-- ticular effect on" the valve 48;" since yit isbalancedf bythe 'decreasing 'forcepn' theopposit'eA surf aceson' theone. side the,diaphragmv 54x and on the otherv side the Valveidisc4'4iLikewise, vthe sub chamber 56 Will have atmospheric pressureimtil'l thesupercharger is started. Therefore., under such; circumstances thfe onlyfrces,. acting on .the valve disc 44'are the `vacuuminV Vthe chamber 321andthe counterbalancingaction,ofthe spring 'lil'.

As the super-charger inthe cabin is, started.the.force'oppcsingthe'spring 1 Qcomprises the difference'between cabinpressurel inthe `subch'amber 5S Aand atmospheric pressure. in theAsubcliamber 58, plus the vacuum in the chamberZl' This iinseats' the"valvedisc 44 more' andi moreY Withint maximum limits` vas the planeAgoes up,A and allowm the atmosphere to enter the chamber 3.2.' Aslongias. the atmosphericpressure is greater,thanthe` vacuumV required forchamber 32,.. there will .,be: ah restricted amoimt of unseating of thevalve, disc 44 so that the pump, continuesto.pullfatlleast some Vvacuuminthe chamben32 When, however; the atmospheric pressure drops,tolwherefritis-f equal to or less than the. vacuum, requiredeinr chamber32,1 the Valve disc. 44 'willgbe-entirelyunseated and the vacuum.necessary fon the instru ment is created bythe atmosphere. This .willlunload the pump entirely. tlis'iunderstocdithat under .theseconditionswthe pressurepin the cabin created by the supercharger exceedsatmospheric; pressure by an amount equal to the forceexertedy on ,disc44 by springfl;

The totall unseating of. disc44. allows: the .in-- strument to operate`on l. thefdiierenti'al between. atmospheric pressureandtheA cabinpressure; and= entirelyY unloads the pumpfso: that the; energylnecessary to pull v`the vacuum -and maintain vitin: the chamber 32 istransferredfto,theemotor-withe consequent savinggin-Ypower.

One -further conditiony must. ordinarily' helmet, when the deviceisfoperated atiexti'eme altitudesi such as, for example, 40,\O00feet.Inj; such alti-U tudes, the atmospheric pressure isf sofflow-that thevacuumli in@ the chamber- 32; is morey than?l thatl necessary`- to;operate the; instrument; and must be balanced in some wayfsog; thatthe-in.

'llliebase 34fisithen clamped against the;75estrumentiwillfnotbegadverselyaiected; For-that purpose, it isdesirable to insert a second throttling valve (not shown) connected tocabin pressure in the instrument line between the instrument and thechamber 32, and operating so that when the vacuum in the instrument linedrops below the necessary amount, the second throttling valve will takesome of the pressure in the cabin and introduce it into the instrumentline thus balancing the vacuum at the point desired.

It is understood that the foregoing description is merely illustrativeof a preferred embodiment of the invention and that the scope of theinvention, therefore, is not to be limited thereto but is to bedetermined by the appended claim.

Iclaim:

A vacuum control valve unit for maintaining a selected differentialpressure for operating flight instruments which are positioned in aregion of fluctuating pressure, including means defining a chamber whichis in communication with a source of vacuum, means for regulating thecommuni-cation of the surrounding atmosphere with said chamber effectiveto maintain said selected differential of pressure, said means includinga valve adapted to control communication between said chamber and thesurrounding atmosphere, resilient means urging said valve in thedirection of closed position, said last mentioned means being operableto allow said valve to open under the influence of the source of vacuum,diaphragm means connected with Ysaid REFERENCES CITED The followingreferences are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,987,666 Carlson Jan. 15, 19352,232,267 Price Feb. 18, 1941 2,194,749 Gregg Mar. 26, 1940 2,308,583Berges Jan. 19, 1943 947,021 Malivert Jan. 18, 1910 767,138 ComstockAug, 9, 1904 1,224,221 Schwanebeck May 1, 1917 1,539,228 Wright May 26,v1925 1,046,884 Spencer Dec. 10, 1912 2,402,499 Lawrence June 18, 19461,142,289 Wadsworth June 8, 1915

